Wyatt Allen 32b03fc76f Applies optimizations to diff comment DOM attachment
A source of latency when creating diff comments in large diffs is the
work needed to reflow the diff DOM to make room for the new comment.
This is particularly evident when adding comments to new files because
the diff is built as an addition group representing the entire file, so
the comment causes a reflow on every subsequent line.

This change optimizes this process in three ways.

* **Limit the size of ADD & REMOVE groups:** The diff processor will now
  break an add or a remove chunk into a series of smaller chunks of the
  same kind. This is controlled by the MAX_GROUP_SIZE constant. In this
  way the number of nodes that need to be reflowed when a comment is
  added to an add or remove group is limited to the number of subsequent
  lines in that group plus the subsequent number of groups.
* **GPU optimize group in general:** Adds CSS properties to diff TBODY
  elements (which correspond to groups, for the most part) that trigger
  GPU acceleration when available.
* **Apply `table-layout: fixed;`** This style speeds up table reflow in
  general.

Change-Id: Ie0e3665b7752fec67f7123cfae70ae99e6f67521
2016-08-11 12:35:31 -07:00

188 lines
5.8 KiB
HTML

<!--
Copyright (C) 2015 The Android Open Source Project
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
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distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
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<link rel="import" href="../../../bower_components/polymer/polymer.html">
<link rel="import" href="../../shared/gr-button/gr-button.html">
<link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
<link rel="import" href="../gr-diff-builder/gr-diff-builder.html">
<link rel="import" href="../gr-diff-comment-thread/gr-diff-comment-thread.html">
<link rel="import" href="../gr-diff-highlight/gr-diff-highlight.html">
<link rel="import" href="../gr-diff-selection/gr-diff-selection.html">
<link rel="import" href="../gr-syntax-themes/gr-theme-default.html">
<dom-module id="gr-diff">
<template>
<style>
:host {
--light-remove-highlight-color: #fee;
--dark-remove-highlight-color: #ffd4d4;
--light-add-highlight-color: #efe;
--dark-add-highlight-color: #d4ffd4;
}
.diffContainer {
border-bottom: 1px solid #eee;
border-top: 1px solid #eee;
display: flex;
font: 12px var(--monospace-font-family);
overflow-x: auto;
will-change: transform;
}
table {
border-collapse: collapse;
border-right: 1px solid #ddd;
table-layout: fixed;
}
table tbody {
-webkit-transform: translateZ(0);
-moz-transform: translateZ(0);
-ms-transform: translateZ(0);
-o-transform: translateZ(0);
transform: translateZ(0);
}
.lineNum {
background-color: #eee;
}
.image-diff .gr-diff {
text-align: center;
}
.image-diff img {
max-width: 50em;
outline: 1px solid #ccc;
}
.image-diff label {
font-family: var(--font-family);
font-style: italic;
}
.diff-row.target-row.target-side-left .lineNum.left,
.diff-row.target-row.target-side-right .lineNum.right,
.diff-row.target-row.unified .lineNum {
background-color: #BBDEFB;
}
.diff-row.target-row.target-side-left .lineNum.left:before,
.diff-row.target-row.target-side-right .lineNum.right:before,
.diff-row.target-row.unified .lineNum:before {
color: #000;
}
.blank,
.content {
background-color: #fff;
}
.lineNum,
.content {
vertical-align: top;
white-space: pre;
}
.contentText:empty:before {
/**
* Insert glyph to prevent empty diff content from collapsing.
* "\200B" is a 'ZERO WIDTH SPACE' (U+200B)
*/
content: "\200B";
}
.contextLineNum:before,
.lineNum:before {
display: inline-block;
color: #666;
content: attr(data-value);
padding: 0 .75em;
text-align: right;
width: 100%;
}
.canComment .lineNum[data-value] {
cursor: pointer;
}
.canComment .lineNum[data-value]:hover:before {
background-color: #ccc;
}
.canComment .lineNum[data-value="FILE"]:before {
content: 'File';
}
.content {
overflow: hidden;
/* Set max and min width since setting width on table cells still
allows them to shrink. */
max-width: var(--content-width, 80ch);
min-width: var(--content-width, 80ch);
}
.content.add .intraline,
.content.add.darkHighlight {
background-color: var(--dark-add-highlight-color);
}
.content.add.lightHighlight {
background-color: var(--light-add-highlight-color);
}
.content.remove .intraline,
.content.remove.darkHighlight {
background-color: var(--dark-remove-highlight-color);
}
.content.remove.lightHighlight {
background-color: var(--light-remove-highlight-color);
}
.contextControl {
background-color: #fef;
color: #849;
}
.contextControl gr-button {
display: inline-block;
font-family: var(--monospace-font-family);
text-decoration: none;
}
.contextControl td:not(.lineNum) {
text-align: center;
}
.br:after {
/* Line feed */
content: '\A';
}
.tab {
display: inline-block;
position: relative;
}
.tab.withIndicator:before {
color: #C62828;
/* >> character */
content: '\00BB';
position: absolute;
}
</style>
<style include="gr-theme-default"></style>
<div class$="[[_computeContainerClass(_loggedIn, viewMode)]]"
on-tap="_handleTap">
<gr-diff-selection>
<gr-diff-highlight
id="highlights"
logged-in="[[_loggedIn]]"
comments="{{_comments}}">
<gr-diff-builder
id="diffBuilder"
comments="[[_comments]]"
diff="[[_diff]]"
view-mode="[[viewMode]]"
is-image-diff="[[isImageDiff]]"
base-image="[[_baseImage]]"
revision-image="[[_revisionImage]]">
<table id="diffTable"></table>
</gr-diff-builder>
</gr-diff-highlight>
</gr-diff-selection>
</div>
<gr-rest-api-interface id="restAPI"></gr-rest-api-interface>
</template>
<script src="gr-diff-line.js"></script>
<script src="gr-diff-group.js"></script>
<script src="gr-diff.js"></script>
</dom-module>